Novel heterocyclic dicarboxylic acids

ABSTRACT

A compound selected from the group consisting of a compound of the formula ##STR1## wherein the dotted lines represent a possible endo or exo double bond, R 1  and R 2  are individually selected from the group consisting of hydrogen, alkyl of 1 to 8 carbon atoms, alkenyl and alkynyl of 2 to 8 carbon atoms, aryl of 6 to 14 carbon atoms, aralkyl of 7 to 18 carbon atoms and ##STR2## R&#39; 2  is alkyl of 1 to 8 carbon atoms or aryl of 6 to 14 carbon atoms, X is --O-- or --NR--, R is selected from the group consisting of hydrogen ##STR3## and --COOR&#39;, R&#39; is hydrogen or alkyl of 1 to 8 carbon atoms, Y is selected from the group consisting of hydrogen, alkyl of 1 to 8 carbon atoms and alkenyl and alkynyl of 2 to 8 carbon atoms, all optionally substituted with at least one halogen or --OH, with the proviso that if Y is --OH, X is not --NH-- and their non-toxic, pharmaceutically acceptable addition salts of acids or bases having antibacterial and immunological properties.

STATE OF THE ART

Related prior art includes European Patent Application Ser. No.0,284,461.

OBJECTS OF THE INVENTION

It is an object of the invention to provide novel compounds of formula Iand their non-toxic, pharmaceutically acceptable salts of acids andbases and a process for their preparation.

It is another object of the invention to provide novel bactericidalcompositions and a method of treating bacterial infections inwarm-blooded animals.

These and other objects and advantages of the invention will becomeobvious from the following detailed description.

THE INVENTION

The novel compounds of the invention are selected from the groupconsisting of a compound of the formula ##STR4## wherein the dottedlines represent a possible endo or exo double bond, R₁ and R₂ areindividually selected from the group consisting of hydrogen, alkyl of 1to 8 carbon atoms, alkenyl and alkynyl of 2 to 8 carbon atoms, aryl of 6to 14 carbon atoms, aralkyl of 7 to 18 carbon atoms and ##STR5## R'₂ isalkyl or 1 to 8 carbon atoms or aryl of 6 to 14 arbon atoms, X is --O--or --NR--, R is selected from the group consisting of hydrogen, ##STR6##and --COOR', R' is hydrogen or alkyl of 1 to 8 carbon atoms, Y isselected from the group consisting of hydrogen, alkyl of 1 to 8 carbonatoms and alkenyl and alkynyl of 2 to 8 carbon atoms, all optionallysubstituted with at least one halogen or --OH, with the proviso that ifY is --OH, X is not --NH-- and their non-toxic, pharmaceuticallyacceptable addition salts of acids or bases.

Examples of suitable acids for the formation of acid addition salts arehydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid,phosphoric acid, acetic acid, formic acid, propionic acid, benzoic acid,maleic acid, fumaric acid, succinic acid, tartaric acid, citric acid,oxalic acid, glyoxylic acid, aspartic acid, alkanesulfonic acids such asmethane acid or ethanesulfonic acid and arylcarboxylic acids.

Examples of bases for the formation of salts are organic mineral basessuch as the alkali metal and alkaline earth metal hydroxides such assodium hydroxide, potassium hydroxide, lithium hydroxide and calciumhydroxide, magnesium hydroxide or ammonium hydroxide and organic basessuch as substituted or non-substituted alkylamines such astrimethylamine, methylamine, propylamine, N,N-dimethylethanolamine ortris(hydroxymethyl) methylamine and basic aminated acids such as lysineor arginine and other bases such as glucosamine or procaine.

Examples of alkyl are methyl, ethyl, propyl, isopropyl and butyl andexamples of alkenyl and alkynyl are vinyl, allyl, ethynyl and propynyl.Examples of substituents on alkyl are at least one halogen such asfluorine or chlorine like --CH₂ F, --CHF₂, --CHCl₂ and --CH₂ Cl, arylsuch as phenyl or aralkyl such as benzyl.

Among the preferred compounds of the invention are the compounds inwhich the dotted lines represent an exo double bond as well as those inwhich the dotted lines do not represent a double bond and their additionsalts with organic or mineral acids or with bases.

Among the preferred compounds are those wherein R₁ and R₂ are hydrogen,those in which Y is hydroxyl radical or acetylene, those wherein X isoxygen atom, those wherein X is NCO₂ R', especially wherein X is NCO₂CH₃ and their addition salts with organic or mineral acids.

The novel process of the invention for the preparation of compounds offormula I comprises reacting a compound of the formula ##STR7## whereinR₁ and R₂ have the above definitions, Y' has either the same values asY, or a precursor of Y and R is CHO or CO₂ alk and alk is alkyl of 1 to8 carbon atoms either with a compound of the formula

    Hal SO.sub.2 alk                                           III

wherein Hal is halogen and alk is alkyl of 1 to 8 carbon atoms to obtaina compound of the formula ##STR8## reacting the latter with an agentfavoring intramolecular nucleophilic substitution to obtain a compoundof the formula ##STR9## or when Y' is hydrogen and R is CHO, with anagent capable of freeing the aminated function to obtain a compound ofthe formula ##STR10## reacting the latter with N-chlorosuccinimide orbenzene sulfonate of 4-formyl-l-methyl-pyridininium, subjecting theproduct to the action of a base and then to the action of a hydrolysisagent to obtain a compound of the formula ##STR11## or when Y' ishydrogen and R is CHO with an oxidizing agent to obtain a compound ofthe formula ##STR12## and if appropriate, the compounds of formulaeI_(A), I_(B) and I_(c) are subjected, to all or only one of thefollowing operations in any order: possible reduction of the endo or exodouble bond; treatment of Y' to obtain Y; total or selective reductionof Y when this is unsaturated; deprotection of the aminated function;and salification.

In a preferred embodiment of the process of the invention, the compoundof formula III is mesyl chloride or tosyl chloride; the agent favoringintramolecular nucleophilic substitution is a base such as potassiumcarbonate or another alkali metal carbonate; the agent capable offreeing the amine function of the compound of formula II is a strongacid such as hydrochloric acid; the base used is diazabicycloundecene ortriethylamine; the hydrolysis agent is oxalic acid; the oxidizing agentreacted with the compound of formula II is JONES reagent or CrO₃ -H₂SO₄, H₂ O; the hydrolysis of the ester functions is preferably carriedout by saponification using a mineral base such as sodium hydroxide orpotassium hydroxide optionally followed by a treatment with an acidresin; the protective group of acetylene is a trimethylsilyl group orany other known group; the cleaving agent of the optional trimethylsilylis potassium fluoride or tetrabutylammonium fluoride or other knownmeans; the hydrogenation catalyst is palladium on activated charcoaleither poisoned or not by quinoline; the deprotection of the aminefunction is carried out with a mineral acid such as hydrochloric acid,or by an organic acid such as trifluoroacetic acid; and the salificationis carried out by the addition of an acid or base to the reactionmedium.

The compounds of formula II used as starting products can be preparedaccording to the process described in published European Patents No.0,284,461 and 0,315,519 and in French Application No. BF 8,905,108.Certain starting compounds which have not been described up until noware described in the experimental part.

In a modification of the process, a compund of the formula ##STR13##wherein alk₁, alk₂ and alk₃ are individually alkyl of 1 to 8 carbonatoms is reacted with mesyl chloride to obtain a compound of the formula##STR14## reacting the latter with a cyclization agent to obtain acompound of the formula ##STR15## and reacting the latter with adecarboxylation agent to obtain a compound of the formula ##STR16##

In a preferred embodiment, the decarboxylation is carried out usingKrapcho's technique.

In another variation of the process, a compound of the formula ##STR17##wherein alk₁, and alk₂ are individually alkyl of 1 to 8 carbon atoms isreacted with an oxidizing agent to obtain a compound of the formula##STR18##

A preferred process comprises reacting a compound of the formula##STR19## wherein alk₁ and alk₂ are individually alkyl of 1 to 8 carbonatoms with a deprotection agent of the amine function to obtain acompound of the formula ##STR20## recting the latter withN-chlorosuccinimide or benzenesulfonate of 4-formyl-1-methyl-pyridinium,then with a base and finally a hydrolysis agent to obtain a compound ofthe formula ##STR21##

The novel bactericidal compositions of the invention are comprised of abactericidally effective amount of at least one compound of formula Iand their non-toxic, pharmaceutically acceptable salts with acids andbases and an inert pharmaceutical carrier. The compositions may be inthe form of tablets, dragees, capsules, granules, suppositories orinjectable solutions or suspen ions.

Examples of suitable excipients are talc, gum arabic, lactose, starch,magnesium stearate, cocoa butter, aqueous or non-aqueous vehicles, fattysubstances of animal or vegetable origin, paraffin derivatives, glycols,various wetting, dispersing or emulsifying agents and preservatives.

Due to their antibacterial and immunological properties, thecompositions are useful for example, in anti-biotherapy vis-a-visbacterial germs, fungi, yeasts (candida albicans . . . ), as an adjuvantin anti-viral therapy, and in anti-cancer chemotherapy, by themselves orin combination, and finally as adjuvants with a standard anti-biotherapyor with vaccination.

The novel method of treating bacterial infections in warm-bloodedanimals, including humans, comprises administering to warm-bloodedanimals a bactericidally effective amount of at least one compound offormula I and their non-toxic, pharmaceutically acceptable salts withbases and acids. The compounds may be administered parenterally,rectally or orally and the usual daily dose is 1,33 to 6,66 mg/kgdepending on the condition treated, the specific compound and the methodof administration.

In the following examples, there are described several preferredembodiments to illustrate the invention. However, it is to be understoodthat the invention is not intended to be limited to the specificembodiments.

EXAMPLE 1 1-methyl-2-ethynyl-4-methylene-1,2,6-piperidine-tricarboxylate(isomer A)

STEP A: 1,2-dimethyl-6-ethyl 4-methylene-2-[2-(trimethylsilyl)-ethynyl]-1,2,6-piperidine-tricarboxylate (isomers A and B)

2.95 g of potassium carbonate were added to a solution of 10 g of7-ethyl-l-methyl6-(methanesulfonyloxy)-2-[(methoxycarbonyl)-amino]-4-methylene-2-[2-(trimethylsilyl)-ethynyl]-heptanedioate[described in preparation 1 of BF 8,905,108] and 90 ml ofdimethylformamide and the reaction mixture was maintained at 90° C.under an argon atmosphere for 3 hours. The product was diluted withether and the mineral salts were filtered off. The mixture wasevaporated to dryness and the residue was chromatographed on silicaeluting with a cyclohexane-ethyl acetate (8-2) mixture to obtain 2.45 gof crude isomer A and 2.72 g of pure isomer B. After a newchromatography on silica and elution with a cyclohexane-ethyl acetate(8-2) mixture, 1.53 g of pure isomer A were obtained. Eluant:cyclohexane-ethyl acetate (8-2); isomer A: Rf=0.26 and isomer B: Rf=0.2.

STEP B: 1,2-dimethyl-6-ethyl2-ethynyl-4-methylene-1,2,6-piperidinetricarboxylate (Isomer A)

0.465 g of potassium fluoride were added to a solution of 1.53 g of theproduct of Step A (isomer A) in 15 ml of dimethylformamide and thereaction mixture was maintained under agitation for 2 hours. Afterdiluting with ether, the mineral salts were filtered off and the organicphase was washed with salt water, followed by drying and evaporating todryness to obtain 1.31 g of product which was chromatographed on silica.Elution with cyclohexane, then with a cyclohexane-ethyl acetate (8-2)mixture yielded 1.016 g of the desired product with a Rf=0.2.

STEP C: 1-methyl 2-ethynyl-4-methylene-1,2,6-piperidinetricarboxylate(Isomer A)

0.41 ml of 2N sodium hydroxide were added to a solution of 103 mg of theproduct of Step B in 1 ml of ethanol and the reaction mixture wasstirred for 24 hours at ambient temperature. 0.1 ml of 2N sodiumhydroxide were added and stirring was continued for 24 hours. Afterconcentrating, the pH was adjusted to 6 and purification took place onDowex 50 W×8 resin to obtain 28 mg of the desired product with a Rf=0.4(eluant: methylene chloride, methanol, acetic acid 80-20-5).

EXAMPLE 2 1-methyl 2-ethynyl-4-methylene-1,2,6-piperidine tricarboxylate(Isomer B)

STEP A: 1,2-dimethyl-6-ethyl 2-ethynyl-4-methylene-1,2,6-piperidinetricarboxylate

Using the procedure of Step B of Example 1, 1,2-dimethyl-6-ethyl4-methylene-2-[2-(trimethylsilyl)-ethynyl]-l,2,6-piperidinetricarboxylate (Isomer B) was reacted to obtain 1.48 g of the desiredproduct with a Rf=0.15 (cyclohexane, ethyl acetate (8-2)).

STEP B: 1-methyl 2-ethynyl-4-methylene-1,2,6-piperidinetricarboxylate(Isomer B)

4.9 ml of 2N sodium hydroxide were added at 0° C. to a solution of 1.39g of the product of Step A and 14 ml of ethanol and the reactionsolution was stirred for 20 hours at ambient temperature. 1 ml of sodiumhydroxide was added and the mixture was stirred for 4 hours at ambienttemperature. After diluting with water, Dowex 50 W x 8 resin was addeduntil a pH of 1 was reached and was then followed by filtering, rinsingwith water, then with ethanol and evporating to dryness to obtain 1.21 gof crude product which was chromatographed on silica eluting with anethanol-ammonium hydroxide (8-2) mixture to obtain 610 mg of the desiredproduct with a Rf=0.2.

EXAMPLE 3 1-methyl 2-ethenyl-4-methylene-l,2,6-piperidine tricarboxylate(Isomer A)

STEP A: 1,2-dimethyl-6-ethyl 2-ethenyl-4-methylene-1,2,6-piperidinetricarboxylate

3.57 g of the product of Step B of Example 1 were dissolved at ambienttemperature in a mixture of 350 ml of ethanol and 0.35 ml of quinolineand then 3.5 g of palladium at 5% on barium sulfate were added.Hydrogenation took place under 1300 mm of mercury, followed byfiltering, rinsing with ethanol and evaporation to dryness to obtain 3.9g of crude product which was purified by successive chromatography onsilica eluting with a cyclohexane-ethyl acetate (8-2) mixture, then by amethylene chloride-ethyl acetate mixture (95-5), then by acyclohexane-ethyl acetate (8-2) mixture to obtain 1.58 g of the desiredproduct with a Rf=0.15 cyclohexane-ethyl acetate (8-2).

STEP B: 1-methyl 2-ethenyl-4-methylene-1,2,6-piperidine-tricarboxylate(Isomer A)

450 mg of the product of Step A were dissolved in 2.5 ml of ethanol andafter chilling, 2.5 ml of sodium hydroxide were added. The mixture wasstirred for 24 hours at ambient temperature and after diluting withwater and chilling, 50 W×8 Dowex resin was added, followed by filtering,rinsing with water, and evaporating to dryness. After filtering thesolution and lyophilizing, 306 mg of crude product were obtained whichwas chromatographed on silica eluting with an ethanol-ammonium hydroxide(8-2) mixture to obtain 228 mg of the desired product with a Rf=0.3.

EXAMPLE 4 1-methyl 2-ethenyl-4-methylene-1,2,6-piperidine-tricarboxylate(Isomer B)

STEP A: 1,2-dimethyl-6-ethyl 2-ethenyl-4-methylene-l,2,6-piperidinetricarboxylate

1.55 g of the product of Step A of Example 2 were dissolved in 150 ml ofethanol and 0.16 ml of quinoline and 1.49 g of palladium at 5% on bariumsulfate wer added to this solution. The suspension was stirred under ahydrogen atmosphere until absorption of the theoretical volume.Filtration took place followed by rinsing with ethanol and evaporatingto dryness to obtain 1.6 g of product which was chromatographed onsilica and eluted with a cyclohexane-ethyl acetae (8-2) mixture toobtain 1.08 g of the desired product with a Rf=0.15.

STEP B: 1-methyl 2-ethenyl-4-methylene-1,2,6-piperidine-tricarboxylate(Isomer B)

936 mg of the product of Step A were dissolved in 10 volumes of ethanoland after chilling, 10 volumes of sodium hydroxide were introduced. Themixture was stirred for 48 hours and the solution was then diluted withwater. Dowex 50 W×8 resin was added until a pH of 2 was reached and themixture was stirred for 2 hours at ambient temperature, followed byrinsing with water, concentrating and lyophilizing to obtain 830 mg ofproduct which was purified by chromatography on silica and eluting withan ethanol-ammonium hydroxide (8-2) mixture, then with water. Afterlyophilizing, 400 mg of the desired product were obtained with a Rf=0.2.

EXAMPLE 5 1-formyl-4-methylene-2,6-piperidine dicarboxylic acid (IsomerA)

STEP A: Triethyl1-(formylamino)-5-(methanesulfonyloxy)-3-methylene-1,1,5-pentanetricarboxylate

Using the procedure of Step A of Example 1, triethyl1-(formylamino)-5-hydroxy-3-methylene-1,1,5-pentatricarboxylate(prepared as in French Patent No. 2,611,721, preparation B) was reactedto obtain the product.

STEP B: Triethyl 1-formyl-4-methylene-2,2,6-piperidine tricarboxylate

Using the procedure of Step B of Example 1, 10 g of the compound of StepA were reacted to obtain 6.95 g of the desired product with a Rf=0.3eluant cyclohexane-ethyl acetate (7-3).

STEP C: Diethyl 1-formyl-4-methylene-2,6-piperidine dicarboxylate

A mixture of 5 g of the product of Step B, 0.8 g of sodium chloride,0.26 g of water and 15 ml of dimethylsulfoxide was stirred for 3 hoursat 165° C. and the mixture was returned to ambient temperature followedby filtering, washing and evaporating to dryness to obtain 4 g ofproduct which was purified on silica eluting with a cyclohexane-ethylacetate (9-1) mixture, then by a cyclohexane-ethyl acetate (7-3) mixtureto obtain 3.1 g of the desired product with a Rf=0.5.

STEP D: 1-formyl-4-methylene-2,6-piperidine dicarboxylic acid (Isomer A)

Using the procedure of Step D of Example 1, 997 mg of the product ofStep C were reacted to obtain 404 mg of the desired product with aRf=0.2, eluant ethanol-ammonium hydroxide (8-2).

EXAMPLE 6 Diethyl cis (±) 4-methylene-2,6-piperidine dicarboxylate ofdiethyl hydrochloride

STEP A: Diethyl 4-methylene-2,6-piperidine dicarboxylate (cis isomer andtrans isomer)

1.5 ml of 12 N hydrochloric acid were added to a solution of 2.8 g ofthe product of Step C of Example 5 and 30 ml of ethanol and the reactionmixture was refluxed for 2 hours. After evaporation to dryness, theresidue was taken up in ethyl acetate and washed with 10% sodiumbicarbonate. The organic phase was dried, filtered and evaporated todryness to obtain 2.0 g of product which was purified on silica elutingwith a cyclohexane-ethyl acetate (8-2) mixture to obtain 0.730 g of thecis product and 0.980 g of the trans product.

STEP B: cis diethyl (±) 4-methylene-2,6-piperidine dicarboxylatehydrochloride

2 ml of a solution of 2N hydrochloric acid in ether were added to asolution of 0.2 g of the cis isomer product of Step A in 5 ml of ethylether and after evaporation to dryness, the residue was taken up inisopropyl ether, followed by filtering and rinsing with isopropyl etherto obtain 0.205 g of the desired product melting at 166° C.

EXAMPLE 7 Trans diethyl (±) 4-methylene-2.6-piperidine dicarboxyltehydrochloride

Using the procedure of Step B of Example 6, the trans isomer base ofExample 6 was reacted to obtain 0.19 g of the desired trans isomer saltmelting at 109° C.

EXAMPLE 8 (±) trans 4-methylene-2,6-piperidine dicarboxylic acid

4.3 ml of a solution of IN sodium hydroxide were added to a solution of10 ml of ethanol and 0.5 g of the trans product of Step A of Example 6.The reaction mixture was stirred for one hour and after appropriatetreatments, 0.23 g of the desired product melting at >250° C. wereobtained.

EXAMPLE 9 (±) cis 4-methylene-2,6-piperidine dicarboxylic acid

3.5 ml of a solution of IN sodium hydroxide were added to a solution of0.4 g of the cis product of Step A of Example 6, and 10 ml of ethanolwere reacted to obtain after appropriate treatments, 0.240 g of thedesired product melting at >250° C.

EXAMPLE 10 (±)trans 1-methyl-4-methylene-1,2,6-piperidine tricarboxylate

STEP A: 2,6-diethyl-l-methyl (trans ±) 4-methylene-1,2,6-piperidinetricarboxylate

0.346 ml of triethylamine were added at 0° C. to a solution of 6 ml ofmethylene chloride and 595 mg of the trans product of Example 6, Step A,and 1.76 ml of methyl chloroformate. The solution was stirred at ambienttemperature for 3 hours, then diluted with methylene chloride, washedwith salt water, dried and evaporated to dryness to obtain 680 mg ofproduct which was chromatographed on silica eluting with acyclohexane-ethyl acetate (75-25) mixture to obtain the desired productwith a Rf=0.3.

STEP B: Trans 1-methyl (±-) 4-methylene-1,2,6-piperidine tricarboxylat

1.45 ml of 2N sodium hydroxide were introduced at 0° C. into a solutionof 391 mg of the product of Step A and 5 ml of ethanol and the mixturewas stirred for 16 hours at ambient temperature. After diluting withwater, Dowex w x 8 resin was added until a pH of 2 was reached. Afterappropriate treatments, 157 mg of the desired product were obtained witha Rf=0,25 (ethanol-ammonium hydroxide 8-2).

EXAMPLE 11 (cis ±) 1-methyl-4-methylene-1,2,6-piperidine tricarboxylate

STEP A: 2,6-diethyl-l-methyl (cis ±) 4-methylene-1,2,6-piperidinetricarboxylate

Using the procedure of Step A of Example 10, 595 mg of the cis productof Example 6 were reacted to obtain after chromatography on silicaeluting with cyclohexane-ethyl acetate (9-1) 480 mg of the desiredproduct with a Rf=0.25 cyclohexane-acetone (8-2).

STEP B: (cis ±) 1-methyl-4-methylene-1,2,6-piperidine tricarboxylate

Using the procedure of Step B of Example 10, 432 mg of the product ofStep A were reacted to obtain 132 mg of the desired product with aRf=0.1 methylene chloride-methanol-acetic acid (95-5-5).

EXAMPLE 12 2-(difluoromethyl)-l-formyl-4-methylene-2,6-piperidinecarboxylic acid

STEP A: Ethvl2-difluoromethyl-l-formyl-4-methylene-2,6-piperidinedicarboxylate

0.39 g of potassium carbonate were added to a solution of 1 g of diethyl2-(difluoromethyl)-2-(formylamino)-4-methylene-6-(methylsulfonyloxy)-heptanedioateprepared as in Example 12, Step F, of European Patent No. 0,315,519 in20 ml of dimethylformamide. The suspension was stirred for 90 minutes atl00° C. to obtain after diluting with ethyl ether, filtering andevporating to dryness, 760 mg of the desired product.

STEP B: 2-(difluoromethyl)-1-formyl-4-methylene-2,6-piperidinedicarboxylic acid

0.68 ml of IN sodium hydroxide were added to a solution of 54 mg of theproduct of Step A in 4 ml of ethanol. The mixture was stirred at ambienttemperature for 60 hours. 4 ml of water were added and the pH wasneutralized to about 6 with Amberlyst 15 resin After filtering andevporating to dryness the residue was taken up in 8 ml of water andlyophilized to obtain 47 mg of the desired product in the form of itssodium salt.

EXAMPLE 13 (±) Ethyl 2-difluoromethyl-4-methylene-2,6-piperidinedicarboxylate (Isomer A and Isomer B)

760 mg of the product of Step A of Example 12 were dissolved in 25 ml ofethanol and 4 ml of 12N hydrochloric acid were added. The reactionmixture was stirred for 2 hours 30 minutes at reflux and 5 ml of waterwere added. The mixture was neutralized with sodium bicarbonate andevaporated to dryness. The residue was taken up in water and extractedthree times with ethyl acetate. After drying and evaporating to dryness,520 mg of product were obtained which was purified by twochromatographies on silica eluting with a cyclohexane-ethyl acetate(9-1) mixture to obtain 225 mg of Isomer A and 185 mg of Isomer B.(Isomer A Rf=0.55 Isomer B Rf=0.50 in cyclohexane-ethyl acetate (6-4)).

EXAMPLE 14 (±) 2-difluoromethyl-4-methylene-2-6-piperidine dicarboxylicacid Isomer (A)

1.2 ml of 2N sodium hydroxide were added to a soluton of 200 mg of theproduct of Example 13 (isomer A) in 7 ml of ethanol and the reactionmixture was stirred for 32 hours at ambient temperature. The pH wastaken to about 5 with 2N hydrochloric acid and after evaporating todryness, the residue was taken up in water, then chromatographed onDowex resin, eluting with water, then 0.7N ammonium hydroxide, then withwater. After evaporation to dryness, 150 mg of crude product wereobtained which was taken up in 20 ml of water. After filtering andlyophilizing , 140 mg of the desired product with a Rf=0.4 eluantbutanol-acetic acid-water (4-2-2) were obtained.

EXAMPLE 15 (±) 2-difluoromethyl-4-methylene-2,6-piperidine-dicarboxylicacid (Isomer B)

1.3 ml of 2N sodium hydroxide were added to a solution of 190 mg of theproduct of Example 13 (Isomer B) in 7 ml of ethanol and the mixture wasstirred at ambient temperature for 30 hours and then neutralized toabout pH 5 with 2N hydrochloric acid. After evaporating to dryness, theresidue was taken up in 5 ml of water, then chromatographed on Dowexresin followed by elution with water. After evaporation to dryness, 140mg of the product were taken up in 200 ml of water, filtered andlyophilized to obtain 130 mg of the desired product with a Rf=0.4Butanol-acetic acid-water (4-2-2).

EXAMPLE 16 1-methyl 2-methyl-4-methylene-1,2,6-piperidine tricarboxylate(Isome A)

STEP A

3.6 g of ethyl2-[(methoxycarbonyl)-amino]-2-methyl-4-methylene-6-(methylsulfonyloxy)heptanedioate prepared as in Example 11, Step E, of European Patent No.0,315,519 were dissolved in 80 ml of dimethylformamide and 1.46 g ofpotassium carbonate were added. The suspension was stirred vigorouslyfor 4 hours at 100° C. and after diluting with ethyl ether, filteringand evaporating to dryness, 3.7 g of crude product were obtained whichwas purified by chromatography on silica eluting with a cyclohexaneethylacetate-methylene chloride (5-2-3) mixture to obtain 1.05 g of pureIsomer A product and 0.56 g of a mixture. The mixture waschromatographed eluting with a cyclohexane-ethyl acetatemethylenechloride (5-2-3) mixture to obtain 300 mg of Isomer B and 50 mg ofIsomer A.

STEP B: 1-methyl 2-methyl-4-methylene-1,2,6-piperidine tricarboxylate(Isomer A)

11.5 ml of 6N sodium hydroxide were added to a solution of 290 mg of theproduct of Step A in 2 ml of ethanol and the mixture was stirred atambient temperature for 4 hours. The pH was taken to 3 with Amberlyst 15resin and after rinsing with water, filtering and evaporation todryness, 225 mg of crude product were obtained which was chromatographedon silica eluting with an ethanol-ammonium hydroxide 95/5-90/10-80/20mixture. After taking up in water, filtering and lyophilizing, 95 mg ofthe desired product with a Rf=0.25 ethanol-ammonium hyroxide (9-1) wereobtained.

EXAMPLE 17 1-methyl 2-methyl-4-methylene-1,2,6-piperidine tricarboxylate(Isomer B)

10 ml of 6N sodium hydroxide were added to a solution of 190 mg of theproduct of Step A of Example 16 (Isomer B) in 2 ml of ethanol and themixture were stirred for 6 days at ambient temperature. The product wasneutralized with Dowex resion and the mixture was rinsed with wateruntil a pH of 3 was reached. After filtering and evaporating to dryness,122 mg of product were obtained which was purified by chromatography onsilica, eluting with a methanol-ammonium hydroxide (80-20) mixutre. Theproduct was evaporated to dryness, then taken up in 20 ml of water.After filtering and lyophilizing, 62 mg of the desired product with aRf=0.2 in ethanol-ammonium hydroxide (9-1) were obtained.

EXAMPLE 18 Diethyl 1-formyl-2-hydroxy-4-methyl-2,6-piperidinedicarboxylate

3.5 ml of Jones reagent [270 g of CrO₃, 400 ml of water and 230 ml of H₂SO₄ plus sufficient quantity of water to make 1 liter were added to asolution of 3 g of the product of Step B below and 60 ml of acetone andthe mixture was stirred for 90 minutes. The excess oxidizing agent wasdestroyed by the addition of isopropanol. Water was added, and themixture was neutralized by the addition of potassium carbonate in powderform. Extraction with methylene chloride was effected followed by dryingon magnesium sulfate, by filtering and evaporation of dryness underreduced pressure to obtain 3.2 g of product which was chromatographed onsilica, eluting with a cyclohexane-ethyl acetate 7-3 mixture to obtain970 mg of the desired product with a Rf =0.20.

Preparation: Diethyl 2-(formylamino)-6-hydroxy-4-methylene heptanedioate

STEP A: Diethyl 2-(formylamino)-6-hydroxy-4-methylene heptanedioate

A solution of 17.9 g of triethyl 1-(formylamino)-5-hydroxy-3-methylene,1,1,5-pentane-tricarboxylate prepared as in French Patent ApplicationNo. 2,611,721, 300 ml of dimethylformamide, 4.87 g of cesium carbonateand 13.15 g of 4-aminothiophenol was stirred for 3 hours at 95° C. Themajority of the dimethylformamide was evaporated off under reducedpressure and 100 ml of ice-water were added. Extraction was effectedwith methylene chloride, followed by washing with 2N hydrochloric acidand salt water. After drying, filtering and evaporation to dryness underreduced pressure, 15.2 g of product were obtained which waschromatographed on silica eluting with a methylene chloride-methanol(98-2) mixture to obtain 11.06 g of the desired product.

STEP B: Diethyl 2-(formylamino)-6-hydroxy-4-methyl heptanedioate

5.74 g of product of Step A, 150 ml of ethanol, 30 ml of pure aceticacid and 1.5 g of 10% palladium were left for 15 hours under a pressureof 10 kg of hydrogen. After filtering, rinsing with ethanol and bringingto dryness under reduced pressure, the oily residue was taken up inmethylene chloride, decanted, dried and brought to dryness to obtain 5.4g of the desired product.

EXAMPLE 19 1-formyl-2-hydroxy-4-methyl-2,6-piperidine dicarboxylic acid(sodium salt)

A mixture of 143 mg of the product of Example 18, 2 ml of ethanol and 1ml of N sodium hydroxide was stirred for 15 hours at ambient temperatureto obtain 155 mg of product which was taken up in water, filtered andlyophilized to obtain 146 mg of the desired product with a Rf=0.35(butanol-acetic acid-ethanol 4-2-2).

EXAMPLE 20 Sodium and 6-ethyl 1-formyl-2-hydroxy-4-methyl-2,6-piperidinedicarboxylate

0.95 ml of N sodium hydroxide were added to a solution of 287 mg of theproduct of Example 18 and 4 ml of ethanol and the mixture was stirredfor 4 hours at ambient temperature then evaporated to dryness underreduced pressure. 5 ml of water were added and extraction took placeseveral times. The aqueous phase was filtered and freeze-dried to obtain258 mg of the desired product with a Rf=0.45 (butanol-aceticacid-ethanol 4-2-2).

EXAMPLE 21 2-hydroxy-4-methyl-tetrahydro-2H-pyran-2,6-dicarboxylic acid(sodium salt)

STEP A: Diethyl 2-amino-6-hydroxy-4-methyl heptanedioate

A mixture of 2 g of diethyl 2-(formylamino)-6-hydroxy-4-methylheptanedioate, 20 ml of ethanol and 2 ml of concentrated hydrochloricacid was stirred at 90° C. and after cooling, 10 ml of water were added.Neutralization took place by the addition of solid sodium carbonate andafter extracting with methylene chloride, drying, filtering and bringingto dryness, 1.7 g of the desired product with a Rf=0.1 (eluant methylenechloride-ethyl acetate (1-1) were obtained.

STEP B: Diethyl 2-hydroxy-4-methyl-tetrahydro-2H-pyran-2,6-dicarboxylate(Isomer A and Isomer B)

840 mg of 4-formyl-l-methyl pyridinium benzensulfonate were added to asolution of 740 mg of the product of Step A, 15 ml of methylene chlorideand 5 ml of dimethylformamide and the reaction mixture was stirred for45 minutes. 1 ml of diazobicyclo[5,4,0]-undec-7-ene was added and thereaction mixture was stirred for 45 minutes. After cooling down to 5-l0°C., 5 ml of a saturated aqueous solution of oxalic acid were added andthe reaction mixture was stirred for 1 hour. Extraction took place withmethylene chloride followed by washing with a solution of sodiumbicarbonate, drying, filtering and bringing to dryness to obtain 630 mgof product which was chromatographed on silica, eluting with acyclohexane-ethyl acetate (9-1) mixture to obtain 160 mg of Isomer A and125 mg of Isomer B.

Isomer A

NMR Spectrum CDCl₃ 400 MHz

0.98 to 1.07 CH₃ --CH;

1.22 to 1.40 m CH₃ --CH₂ ; 1.4 to 3.05 m the CH₂ 's and CH--CH₃ 's; 4.51(dd) the 2 types of ##STR22## 4.66 (dd); 4.6 to 4.40 (m) --CH₂ --CH₃ ofCO₂ CH₂ CH₃.

Isomer B

NMR Spectrum in CDCl₃ 400 MHz;

0.99 (d) CH₃ --CH;

1.28 (t) 1.34 (t) CH₃ --CH₂ ;

2.00 (m);

    ______________________________________                                         1.71 (dd) J = 13 and 11 Hz                                                                           the CH.sub.2 's of the ring                           1.75 (dd) J = 13 and 4 Hz                                                     ______________________________________                                    

2.14 (m) CH₃ --CH--CH₂.

STEP C: 2-hydroxy-4-methyl-Tetrahydro-2H-pyran-2,6-dicarboxylic acid(sodium salt)

A mixture of 111 mg of a mixture of Isomer A and B of Step B, 3 ml ofethanol and 0.85 ml of N sodium hyroxide was stirred for one night. Themixture was evaporated to dryness under reduced pressure and a few ml ofdistilled water were added. After filtering and lyophilizing, 91 mg ofthe desired product were obtained.

    ______________________________________                                         ##STR23##                                                                     ##STR24##                                                                    CHCO.sub.2 Na4.08 4.27 dd: J=13                                               ______________________________________                                    

EXAMPLE 22 Sodium2-hydroxy-4-methyl-tetrahydro-2H-pyran-2,6-dicarboxylate (Isomer B)

Using the procedure of Step C of Example 21, Isomer B of Step B ofExample 21 was reacted to obtain the desired product.

NMR D₂ O 300 MHz

CH₃ in position 4:0.95 (d J=6.5)

Hydrogens of ring in positon 3,4,5:1.15 (q J=13);

1.35 (t J=13);

1.77 (m), 1.97 (m);

Hydrogen of ring in position 6:4.08, 4.27 (dd J=13).

EXAMPLE 23 Sodium2-hydroxy-4-methyl-tetrahydro-2H-pyran-2,6-dicarboxylate (Isome A)

Using the procedure of Step C of Example 21, Isomer A of Step B ofExample 21 was reacted to obtain the desired product.

NMR D₂ O 300 MHz

CH₃ in position 4:0.96 (d J=6.5)

Hydrogens of ring in positions 3,4,5:1.21 (d J=7), 1.25 to 3.0

Hydrogen of ring in position 6:4.08, 4.27.

EXAMPLE 24

Tablets were prepared conta[ning 50 mg of the product of Example 1 andsufficient excipient for a tablet of 250 mg of lactose, starch, talc andmagnesium stearate.

EXAMPLE 25

Capsules were prepared containing 100 mg of the product of Example 21and a standard excipient for capsules.

Antibacterial activity (in vitro)

The antibacterial activity of the claimed products was determined by thediffusion method in Davis Mingioli medium with 1% agar added. Thegeloses used were poured into Petri dishes at 48° C., after seeding at5×10⁵ germs/ml using the test bacterial strain. The inocula came from a24 hour pre-culture in a Davis Mingioli culture medium. After hardeningthe geloses, the aqueous solutions of the studied products wereintroduced into 9 mm wells hollowed out in the medium using a hollowpunch. The observed inhibition zones (diameter in mm) were measuredafter incubation for 24 hours at 37° C.

    ______________________________________                                                   Product of                                                                             Product of                                                                              Product of                                                 Example 1                                                                              Example 2 Example 22                                                 (100 mg/l)                                                                             (100 mg/l)                                                                              (100 mg/l)                                      ______________________________________                                        Escherichia  17.5       18                                                    coli 078                                                                      Salmonella   31         34        19                                          typhimurium MZ11                                                              Enterobacter 26         29                                                    cloacae 1321E                                                                 Providencia  29         28                                                    sp. DU48                                                                      ______________________________________                                    

Various modifications of the products and method of the invention may bemade without departing frm the spirit or scope thereof and it should beunderstood that the invention is intended to be limited only as definedin the appended claims.

What is claimed is:
 1. A compound selected from the group consisting ofa compound of the formula ##STR25## wherein the dotted lines representan optional double bond, R₁ and R₂ are individually selected from thegroup consisting of hydrogen, alkyl of 1 to 8 carbon atoms, alkenyl andalkynyl of 2 to 8 carbon atoms, phenyl, benzyl and ##STR26## R₂ is alkylof 1 to 8 carbon atoms or aryl of 6 to 14 carbon atoms, X is --NR--, Ris selected from the group consisting of H, --CH, --COOR', R' ishydrogen or alkyl of 1 to 8 carbon atoms, Y is selected from the groupconsisting of hydrogen, alkyl of 1 to 8 carbon atoms and alkenyl andalkynyl of 2 to 8 carbon atoms, all optionally substituted with at leastone halogen or --OH and their non-toxic, pharmaceutically acceptableacid addition salts of acids and bases.
 2. A compound of claim 1 whereinthe dotted lines are a double bond.
 3. A compound of claim 1 wherein thedotted lines are not a double bond.
 4. A compound of claim 1 wherein R₁and R₂ are hydrogen.
 5. A compound of claim 1 wherein Y is --C.tbd.CH.6. A compound of claim 1 wherein X is --N--COR'.
 7. A compound of claim6 wherein R' is --CH₃.
 8. A compound selected from the group consistingof 1-methyl 2-ethynyl-4-methylene-l,2,6-piperidine tricarboxylate(Isomer A and B) and their non-toxic, pharmaceutically acceptableadditon salts with acids and bases.
 9. A bactericidal compositioncomprising a bactericidally effective amount of at least one compound ofclaim 1 and an inert pharmaceutical carrier.
 10. A composition of claim9 wherein the dotted lines are a double bond.
 11. A composition of claim9 wherein the dotted lines are not a double bond.
 12. A composition ofclaim 9 wherein R₁ and R₂ are hydrogen.
 13. A composition of claim 9wherein Y is --C.tbd.CH.
 14. A composition of claim 9 wherein X is##STR27##
 15. A composition of claim 14 wherein R' is --CH₃.
 16. Acomposition of claim 9 wherein the active compound is selected from thegroup consisting of 1-methyl 2-ethynyl-4-methylene-1,2,6-piperidinetricarboxylate of (Isomer A and B) and their non-toxic, pharmaceuticallyacceptable addition salts with acids and bases.
 17. A method of treatingbacterial infections in warm-blooded animals comprising administering towarm-blooded animals a bactericidally effective amount of at least onecompound of claim
 1. 18. A method of claim 17 wherein the dotted linesare a double bond
 19. A method of claim 17 wherein the dotted lines arenot a double bond.
 20. A method of claim 17 wherein R₁ and R₂ arehydrogen.
 21. A method of claim 17 wherein Y is --C.tbd.CH.
 22. A methodof claim 1 wherein X is ##STR28##
 23. A method of claim 22 wherein R' is--CH₃.
 24. A method of claim 17 wherein the active compound is selectedfrom the group consisting of 1-methyl 2-ethynyl-4-methylene-1,2,6-piperidine tricarboxylate (Isomer A and B) and their non-toxic-pharmaceutically acceptable addition salts with acids or bases.